SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '194c7b8923840d523231a86c6c9c03e196b7a89599d374402fc028531b9ee2d4' 
  AND token = 'VYMocpx/53D++jzoGxrYwhrAf+gqO8aAUqtznPjxJok=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}